In general, solid material may exist in an amorphous state, a polycrystalline state, and/or a single crystalline state.
Because atoms included in a material having an amorphous state are irregularly arranged, a material having an amorphous state may not be electrically conductive.
A material having a polycrystalline state may have crystal structures of various sizes, shapes, and/or orientations. Within the crystal structures, atoms may be arranged in an orderly fashion. However, there are grain boundaries between the crystal structures that may inhibit the movement of carriers, such as electrons and/or holes, in the material. As a result, the electrical characteristics of a polycrystalline material may be relatively poor.
A material having a single crystalline state has a crystal structure of one type, where atoms are arranged in an orderly pattern in the crystal structure. Thus, a material having a single crystal structure may not have a large number of grain boundaries therein. As a result, the electrical characteristics of a material having a single crystalline state may be substantially superior to those of a material having a polycrystalline state.
Accordingly, a semiconductor device having a multi-layered structure, such as a thin film transistor (TFT) or a system on chip (SOC), may generally include at least one single crystalline member.
However, when a single crystalline member is grown epitaxially, a void or voids may be formed between the single crystalline member and an insulation member that is adjacent to the single crystalline member.
In addition, when a single crystalline member is grown epitaxially, a void or voids may be formed between adjacent single crystalline members.